This invention relates to a cupola and more particularly to a cupola which receives a portion of its heat input from a plasma torch so fuels other than coke may be utilized.
The cupola is a vertical cylindrical shaft furnace in which normally alternate layers of coke, metal scrap and fluxing material such as lime stone are layered and the coke is ignited and burned melting the scrap to make iron. In the plasma fired cupola part of the heat energy is supplied by a plasma torch.
U.S. Pat. No. 4,530,101 describes a plasma-fired cupola where plasma torches are utilized to melt metal turnings in nozzles which are connected to the lower end of the cupola.
A related application entitled "PLASMA-FIRED FEED NOZZLE" filed May 8, 1987 and assigned Ser. No. 47,811 describes how a plasma torch and nozzle are attached to the cupola and may be utilized to feed particular material and gases to the lower portion of the cupola.
An application entitled "PLASMA-FIRED CUPOLA" filed on May 8, 1987 and assigned Ser. No. 47,809 describes how the plasma-fired cupola can be utilized to melt turnings and fine chips making up approximately 75% of the metal charge in the cupola.
An application entitled "CONTROL OF A PLASMA-FIRED CUPOLA" filed May 8, 1987 and assigned Serial No. 47,810 describes how the plasma-fired cupola is controlled. A paper published by the inventor July 1985 entitled "Test Results of a Pilot Scale Plasma-Fired Cupola for Iron Chip Melting" describes the apparatus and some of the test results from operating the apparatus. However, there is no suggestion of replacing the coke with coal or very fine coke.